Process of dehydrating perborates.



UNITED STATES PATENT OFFICE.

OTTO LIEBKNECHT, OF FBANKI'ORT-ON-THE-MAIN, GERMANY, ASSIGNOB TO BOE-SSLER & HASSLACHEB CHEMICAL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

No Drawing.

To all whom it may concern:

Be it known that I, Ono LIEBKNEOHT, a subject of the Emperor of Germany, residing at Frankfort-on-the-Main, Germany, have invented certain new and useful Improvements in Processes of Dehydrating Perborates.

This invention relates to a process for the dehydration of perborates, such as alkaliperborates carrying water as a constituent when in the crystallized state, and it particularly refers to a process for the dehydration of the crystals of the well known sodium perborate NaBO,.4H,O, carrying 10.4% of active 0a gen, by means of alcohols, whereby a sodium perborate of higher ox en content is obtained.

T e crystallized sodium-perborate of the formula NaBO II LO shows a rather remarkable tendency to decompose and in order to separate the water of crystalliza tion from the compound the only way known-at the present consists in heating the same in cacao at a gentle temperature: this process has proved unsatisfactory, however, because of its slowness and the losses of oxygen sustained thereby.

The advantages of my invention are great and important inasmuch as they provide a new and valuable method for producing a perborate, such as sodium perborate, of 14'16% active oxygen, the operation being carried out in a very short time and without any losses of oxygen Whatever.

he new process consists for example, in heating one art of crystallized sodiumperborate, Na%O,.4H,O, with 3-5 parts of an absolute or nearly absolute alcohol to a temperature of about 5070 C. I prefer to stir the mass during the heating and sno ceed, in a very short time, in splitting off p'racticall all the water of crystallization; the dehy rated sodium-perborate thus obtained isa very fine powder and may easily be dried when removed from the filter.

As stated above, there is no loss of active oxygen from the sodiumerborate and the process is the more remar able inasmuch as the sodium-perborate does not exert any oxidizing efl'ect on the alcohols serving as dehydrating agents, for instance, even methyl alcohol, usually most readily undergoing oxidation, is not affected by the process.

In order to illustrate the new process more fully the following example is given: 500

Specification of Letters Patent.

Application filed November 15, 1912. Serial No. 731,513.

PROCESS OF DE'HYDRATIN G PEBBORATES.

Patented June 2. 1914.

parts of sodium-perborate, carrying 10.37%

of active oxygen, and 2000 'parts ofabsolute,

or practically absolute, ethyl alcohol are heated for thirty minutes in a suitable reaction vessel, provided with'a. stirrer, up to a temperature of about drated sodium-perborate is then obtained from the mass by filtering and subsequent drying in any of the Well known ways. If preferable the alcohol adherin to the so dinm-perbomte may be removef by washing with ether. The sodium-perborate thus finally obtained by the process described above mounts to 327 parts and carries a con tent of 15.6% of active oxygen.

It is obvious that alcohol, having" once passed through the process, carries consid; erable quantities of Water and accordingly! will furnish, if used again immediately, a sodium-perborate carrying a content of only l2l4% of active oxygen. By rectifying or treat-in the alcohol with burned lime or the like we 1 known means, alcohol having once served as a dehydration agent in the process, may be regenerated to itsabsolute strength to serve again as a dehydrating agent and to thus continuously pass through the process in a cyclic way.

It is evident that, the process may be carried on without strictly adhering to the pro- C. The dehvportions of parts given in the aboveexample,

which, as well as the mechanical manipulations of the operation, mav be greatly varied without departing from the nnciple of the invention. Furthermore it IS not necessary to carr on the operation exclusively with ethyl a cohol inasmuch as any other alcohol, as for instance methyl alcohol and the like, will serve to achieve the purpose in view.

The merits of the process are not exclusively limited to the sodium-perborate NaBO,.4H,O, but may also be extended to any of the other existing perborates as for instance to the sodium-perborate.

Finally it is not necessary to supply the pen borate to the process when in the dry state, but wet crystals also, coming directly from the filtering apparatus, may be immediately submitted to the process so that in the latter case the drying of the perborate crystals and the dehydration of the same may be combined into one operation.

Where I use the term alcohol in the claims I mean to include diluted as well as absolute or nearly absolute or approximately absolute alcohol and where I use the term crystallized I mean to include crystalswhether in the dry or the wet state.

Having described my invention, what I claim and 'desire to secure by Letters Patent is:

1.-A process of dehydrating perborates consisting in dehydrating a crystallized erborate by heating the same in presence 0 an alcohol. 1.

2. A process of dehydrating perborates consisting in dehydrating a crystallized perborate by heating the same to a temperature of from 50 to 70 C. in presence of an alcohol.

3. Av process of dehydrating alkali-perborates consisting in dehydrating a crystallized alkali-perborate by heating the same in presence of an alcohol.

4. A process of dehydrating alkali-perborates consisting in dehydrating a crystat lized alkali-perborate by heating the same to a temperature of from 50 to 70 C. in presence of an alcohol.

5. A process of dehydrating sodium-perborates consisting in dehydrating a crystallized sodium-perborate b heating the same in presence of an alooho 6. A process of dehydrating sodium-per borates consisting in dehydrating a crystallized sodiuin-perborate by heating the same to a temperature of from 50 to 70" C. in presence of an alcohol.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

OTTO LIEBKNECHT. \Vitnesses:

JEAN GRUND, CARL GRUND.

Copies of this patent may be obtained for the cents each, by addrentng the Commissioner of Patents,

Washington, D. O.

It is hereby certified that in Letters Patent No. 1,098,740, granted June 2, 1914,

upon-the application of Otto Liebkneeht, of Fnmkfort-on-thc-Main, Germany, {or an improvement in Processes of Dehydrating Perborates, errors appear in the printed specification requiring correction as follows: Page 1, line 69, for the word mounts read amovmts; same page, line 99, strike out the period; and that the said Letters Patent should be read with these corrections therein that the s ame may eonform to the record of the ease in the Patent Office.

Signed and sealed this 14th day of July, A. D., 1914.

SEAL J. 'r. NEWTON,

Acting Commissioner of Patents. 

